Some power transmission mechanisms, for example automotive transmissions, employ planetary gearsets that operate at high performance levels, which may include high speed or high centrifugal loading. As such, the planetary bearings require lubrication for reliable operation and thermal stability. In some transmissions, planet pins having an axial hole in fluid communication with radial holes are provided to deliver a lubrication fluid, for example oil, from a source such as an “oil dam” or a “lube catcher” to the planetary bearing during operation.
Current planetary gear systems may include a lubrication system having planet pins, each with an axial hole and one radial hole passing through opposite walls of the pin. These planet pins must be installed oriented rotationally (“clocked”) such that the axis of the radial hole corresponds with a position between about 11 o'clock and about 1 o'clock (approximately 0°±30° from vertical) when in the normal operating position in order that oil may pass from the axial hole to the radial hole and into the planetary bearing. Incorrect installation is associated with premature failure of the planetary gear system. An alignment feature, for example a notch, may be provided to aid in proper orientation of the planet pin. However, the assembly process requires careful attention, orientation of the planet pins, and resultant slower assembly speeds to assure proper placement of the planet pins.
Accordingly, a need exists for an improved planet pin for use in a planetary gear system.